Project Summary/Abstract Genetically engineered tumoricidal neural stem cells (tNSCs) are a promising therapy for the highly aggressive brain cancer Glioblastoma (GBM). Engineered tNSCs have unique tumor-homing capacity that allows them to deliver anti-cancer gene products directly into local and invasive GBM foci. We recently discovered that polymeric scaffolds significantly increase the survival of therapeutic stem cells in the GBM resection cavity, remained permissive to stem cell tumoritropic homing, and markedly prolong the survival of mice with post-operative GBM. Yet, limitations to scaffold design are likely to prevent the effective application of scaffold/tNSC therapy in a clinical setting. Additionally, the matrix properties that regulate tNSC therapy are unknown, preventing the optimization of scaffold parameters in order to develop a scaffold/tNSC treatment that is effective against post-surgical GBM in patients. Our results show that altering fiber diameter and gelatin doping within scaffolds improves tNSC transplant. This allows us to hypothesize that optimizing the design features of scaffolds will achieve effective suppression of post- surgical GBMs by tNSC therapy. We propose to identify the scaffold features that promote tNSC cancer therapy by using a panel of scaffolds with different biophysical and biochemical features known to influence stem cell adherence, movement, and differentiation. We will then determine the ability of scaffolds incorporating multiple optimized features to improve tNSC therapy using surgical resection models of patient- derived human xenografts in immune-depleted mice and syngeneic GBM allografts in immune-competent animals. We propose to undertake the following Aims: 1) Develop and characterize a panel of polymeric scaffolds with differing topographic, mechanical, and biochemical properties; 2) Determine the scaffold design parameters that regulate tNSC therapy for post-operative GBM; 3) Investigate the efficacy and safety of tumoricidal tSC therapy in immune-competent models of GBM resection/recurrence. The results of our study will generate a therapeutic tNSC/scaffold transplant strategy capable of robust GBM killing that can be translated for human patient testing. It will also uncover the scaffold features that regulate different aspects of tNSCs, allowing us to modulate tNSC cancer therapy through matrix design.